Bone plate



June 15, 1948. K. TOWNSEND ET AL- 2,443,363

. BONE PLATE Filed A ril 13, 1942 a I fi r anei' z, .ZbzqnsendWGZEZZWENTORS Patented June 15, 1948 BONE PLATE? Kenneth Townsend andiCharlesrw-nGilfillama-g Hollywood, Calif.

Application April 13, 194258crialfNoi438i838 2 Glaimsa (Cl. 1284-9929Our invention relates to the art of bone setting, and-*has among itsobj-eets and advantages -s.

theprovisionM an-improved 'b'o'ne plate.-"=--- In accompanying drawingFigure- 1 is a View of afi-"a'c'tl ired iemurillu's-fi tratingourinvention applied-thereto Figure 2 is a face.viewvofe-the-bone platestructure applied to the femur of Figure 1;

Figure -3 is a sectionalview -taken along the Figure 4 is aperspective-wievc-of-porti'ons of two overlapping bone plates.

Iii theembodiment seleeted iot illhstratingthe drawing illustrates twooverlapping bone plates l secured to the fractured femur 42 by means ofscrews M. The plates I5 are identical. Our bone plate is made ofaustenitic (hardened by cold working) stainless steel. The non-corrosivealloy prefer-ably contains eight per cent of nickel and eighteen percent of chromium. The bone plate is 20 cm. in length, 1.4 cm. in widthand 0.4 cm. in thickness. A series of slots It for the screws I4 isprovided along the longitudinal medial line of the plate, which slotsare 1 cm. in length with widths slightly larger than the 6-32 or 6-20machine screw. The slots are spaced 1 cm. apart.

The two marginal side edges of the plate are deformed to provideV-shaped contours l8 wherein the outside flanges 20 are considerablywider than the inside flanges 22 so as to bring the flanges 20 into boneengagement with the body of the plate spaced from the bone.

In operation, the plate may be cut at the operating table to the desiredlength. If necessary, the plate may then be molded or contoured to thebone contour through the aid of pliers. While an assistant approximatesthe fragments with bone-holding forceps, the plate is applied to theexposed bone, and holes (#36 drill) are drilled in the middle of theslots l6, through both cortices, and the screws inserted. The screws Mare of the fluted type, which renders the screws self-tapping.

The longitudinal slots l6 are characterized by many advantages over theconventional round or countersunk screw holes. The fracture need not bein apposition when the plate is applied. The ends of the fracture may bemore than one quarter inch apart. The screws are sunk to light contactwith the plate, pressure is then applied above and below on thefractured member, the fracture thereby being accurately reduced. Thescrews are then tightened. After muscle tone has been restoredpostoperatively, the pull only 5.4% The =plate f isxtcorrugatedlongitudinally [to the":

contour 'ofi-ia :mo'difiedeMr-in crossrarsectionywhich allows maximumstrength inia. plate of relatively thin auge metalsii The corrugated"cross section is of uch contourcasito iallowon-ly the -two outer" a flanes:.-.-to comexinanwntact with: .the 1 bone, thus havingrelativelysmallb'one contact;:.which allows tends to furthers reduce:thearlfra'ctured-r surfaces promoting quichenhealingnPlastermasts-areeune' nece-ssary,- light-suspension: or;traction--beingused "A for a short-period, tor walkingcalipers:

new bone to form unclercthearbody of the plate: Tli'e corrugated contourofrthetplate wheri, ap-

plied te th convexisurface of theszboneyatends to:

maintain the original longitudinal axis of the fractured bone fragments.The plate action prevents lateral stresses on the shafts of the screwsused to hold the plate, which helps to prevent loosening of the screws.Figures 1 and 2 illustrate two stacked plates, such stacking beingdesirable in connection with femurs, large humeri and tibiae. For doublefractures of the femur, tibia or humerus, i. e., where fractures involvethe upper third and lower third of the bone, thereby producin a freefragment, the plates may be overlapped and staggered end-wise tomaintain a continuous metal truss. In connection with conventionalplates, this type of fracture necessitates two plates without continuousmetal bridging. The corrugated contour allows the plates to be stackedor nested for additional strength as needed. Such stacking of the platesprovides a leaf spring action, which counteracts sudden stresses in thefractured member, caused by sudden muscle contracture or spasm, fallingof the patient, or undue early weight bearing of the patient. Because ofthe overlapping coaction of nested plates, one or more free fragments ofbone may be completely bridged with a metal truss. The thin gauge of theplate allows it to be cut at the time of the operation, when the exactlength has been decided upon. Thus many plates of diiferent lengths arenot required as is necessary with the conventional bone plates.

' The plate is easily bent to the longitudinal contour of the bone, evento right angles, without danger of breaking the plate. This is done atthe time of the operation with the field exposed.

The slots through which the screws l4 pass allow the muscle pull to moreclosely approximate the fracture surfaces. In connection withconventional plates, the cortex on the plate side is often held apartwhile the opposite cortex is closely approximated, thus permitting unduestrain on the plate. Whether the plates are used singly or in nestedrelationship, the cross sectional end contour and the slotted featurefunction in the same manner. The combined strength of the two plates isgreater than two individual plates because of the leaf spring action.The fluted end of the screw M has an eccentric point formation and thefluted formation extends a considerable distance longitudinally of thescrew. Such a screw allows a smaller hole to be used in the bone withgreater holding power, and with about forty percent greater tappingease.

Without further elaboration, the foregoing will so fully illustrate ourinvention, that others may, by applying current knowledge, readily adaptthe same for use under various conditions of service.

We claim;

1. A combination brace for fractured bones comprising a plurality ofcomparatively thin elongated plates in laminated relation providing aleaf spring-like brace, each of said plates having the same shape incross section providing nesting thereof, and each of said plates havinga centrally disposed flat web with inverted V-shape flanges at the edgesand with the outer legs of said V-shape flanges longer than the innerlegs providing means spacing the centrally disposed Web from a planeacross the outer edges of the outer legs of the flanges, said centrallydisposed webs having spaced elongated centrally positioned screwreceiving slots therein adapted to register with the plates nested withthe ends aligned and also with the plates staggered.

2. A connecting plate for fractured bones comprising an elongated stripof material having spaced slots therein extending continuouslythroughout the length thereof, and in which the said strip, in crosssection, comprises a flat intermediate area in which. the slots arepositioned, with the sides of the strip at the edges of the flat areaextending upwardly and then downwardly assuming V-shapes with theextreme edges positioned below the plane of the said flat area therebyspacing the flat area from a plane corresponding with the said extremeedges providing a springy gripping action of the said plate with a boneon which it may be secured by screws through the said slots.

KENNETH TOWNSEND.

CHARLES W. GILFILLAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,018,452 Slaughter Feb. 27, 19121,025,008 Miner Apr. 30, 1912 1,105,105 Sherman July 28, 1914 2,133,859Hawley Oct. 18, 1938 FOREIGN PATENTS Number Country Date 19,736 GreatBritain Sept. 9, 1902 OTHER REFERENCES Bickhams Operative Surgery, 1924,vol. 2, pp. 362 and 369.

